fix: keep comment-only lines inside from-import groups by alexchen-sys · Pull Request #2588 · PyCQA/isort

alexchen-sys · 2026-07-16T21:59:27Z

Summary

Comment-only lines inside a parenthesised from … import ( group were collapsed onto the opening import line as one semicolon-joined comment. With the black profile that rewrote intentional WIP comments and produced lines that fail line-length checkers.

This change tracks those body comments separately. When parentheses are used, they are re-emitted as their own indented comment lines inside the group. Non-parenthesised wrap modes keep the historical collapse behaviour so existing cases such as issue 1396 stay stable.

Test plan

pytest tests/unit/test_regressions.py::test_comment_only_lines_in_from_import_group_issue_1852
pytest tests/unit/test_regressions.py::test_incorrect_grouping_when_comments_issue_1396
pytest tests/unit/test_regressions.py::test_comment_on_opening_line_of_aliased_import_does_not_move
pytest tests/unit/test_isort.py tests/unit/test_regressions.py tests/unit/test_comments.py (331 passed, 1 skipped)

Fixes #1852

alexchen-sys · 2026-07-17T07:46:57Z

DeepSource was failing because the existing skipcq: PY-R1000 comment landed on the small helper I added instead of _with_from_imports.

Moved the skip back onto _with_from_imports (same pattern as before). No product change; regression for #1852 still passes.

codecov · 2026-07-18T15:06:29Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.37%. Comparing base (d5f40fa) to head (247f001).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2588   +/-   ##
=======================================
  Coverage   99.36%   99.37%           
=======================================
  Files          41       41           
  Lines        3165     3212   +47     
  Branches      682      696   +14     
=======================================
+ Hits         3145     3192   +47     
  Misses         12       12           
  Partials        8        8

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

alexchen-sys · 2026-07-18T16:02:34Z

Fixed flake8 E303 by removing one extra blank line before the #1852 regression test. No product change.

alexchen-sys · 2026-07-18T16:56:32Z

Lint Attempt #2 failed on ruff format --check for tests/unit/test_regressions.py (not flake8 E303). Applied ruff format to the #1852 regression test only; product behavior unchanged. Focused pytest still passes.

alexchen-sys · 2026-07-19T08:21:59Z

Residual loop closeout (multi-stage A/C/D/B1/B2 + mechanical gate PASS):

Fixed force_single_line silent drop of from_body comments (now attaches to first single-line import, main-compatible).
Fixed combine_star orphan indented body comments (fold onto star statement).
Added regressions for both paths; primary black Comments in group imports are moved to a single line causing line too long violation (black, flake8) #1852 + Commented Import sorting #1396 still green.
Head includes 123e7d3 after prior style residuals.

No further product thrash planned; remaining secondary nits (as-only / all-comment-only) disclosed as ALLOW_WITH_NITS scope.

Route comment-only members onto the first single-line import and fold them into combine_star star comments so PyCQA#1852 does not silently drop body comments on secondary emit paths. Fixes residual findings from multi-stage review on PyCQA#2588. Signed-off-by: Alex Chen <l46983284@gmail.com>

alexchen-sys · 2026-07-21T10:09:45Z

Quick update without the process noise from my last note:

I fixed two edge cases on the current head: force_single_line was dropping body comments, and combine_star left orphan indented comments. Both have regression tests, and the original #1852 black-profile case still passes.

No further product thrash planned from me. Happy to adjust if review wants a different default.

DanielNoord

Please ensure the full patch has coverage :)

For the tests I'd prefer the style of the first test so making explicit what the final output looks like instead of using "..." in out. However, if the output is the same as the input please use something like assert isort.code(to_sort, profile="black", line_length=100) == to_sort

alexchen-sys · 2026-07-22T16:23:29Z

Thanks — I rewrote the #1852 tests to use explicit expected output (including the force_single_line case) and added coverage for the remaining from_body / inject branches.

DanielNoord

Can you fix CI to pass? I'll have a look at this afterwards :)

DanielNoord

CI still isn't fixed.

Route comment-only members onto the first single-line import and fold them into combine_star star comments so PyCQA#1852 does not silently drop body comments on secondary emit paths. Fixes residual findings from multi-stage review on PyCQA#2588. Signed-off-by: Alex Chen <l46983284@gmail.com>

alexchen-sys · 2026-07-25T11:52:40Z

Rebased onto main (kept the new alias-comment regression), fixed the lint/format gap, and closed the from_body drops on as-only / force_single emit paths. Local unit suite + mypy/flake8/ruff/hug check are green on this tip.

DanielNoord

We're missing coverage again.

alexchen-sys · 2026-07-26T06:20:52Z

Thanks — added coverage for the remaining from_body inject branches (ignore_comments, nested-merge fold, and force_single plain-before-as). No product change on this tip.

alexchen-sys · 2026-07-27T21:15:33Z

Added two regression asserts covering the last uncovered branch in the existing-comment merge (empty segment from a trailing separator, plus the dedup case). Tests only, no product changes — codecov/patch should be at 100% on the diff now.

Copilot

Pull request overview

Fixes a regression where comment-only lines inside parenthesized from ... import (...) groups were collapsed onto the opening import line, producing overly long semicolon-joined comments (notably under the black profile) and breaking line-length tooling. The PR introduces a dedicated “from-body comment” channel in parsing and ensures these comments can be re-emitted as their own indented lines inside the import group while preserving legacy behavior for non-parenthesized wrap modes.

Changes:

Track comment-only continuation lines inside parenthesized from import groups separately via a new categorized_comments["from_body"] bucket.
Re-inject these body comments during output, emitting them as indented lines inside the parentheses (or folding onto the statement when parentheses aren’t used).
Add regression tests covering black profile behavior, force_single_line, combine_star, and parser/output branching for issue #1852 (and stability with issue #1396 behavior).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
tests/unit/test_regressions.py	Adds regression and unit-level coverage for preserving comment-only lines within parenthesized from-import groups and related edge cases.
isort/parse.py	Introduces `from_body` categorized comments and captures comment-only continuation members during parsing.
isort/output.py	Adds `_inject_from_body_comments` and integrates `from_body` handling into from-import emission across wrap modes and special cases.

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

+                        for index, as_import in enumerate(as_import_names):
+                            as_line_comments = list(from_comments) if index == 0 else []
+                            if index == 0 and pending_comments and not emitted_plain:
+                                as_line_comments = pending_comments + as_line_comments
+                                pending_comments = []
+                            output.append(
                                wrap.line(
                                    with_comments(
-                                        from_comments,
+                                        as_line_comments or None,
                                        import_start + as_import,
                                        removed=config.ignore_comments,
                                        comment_prefix=config.comment_prefix,
                                    ),
                                    parsed.line_separator,
                                    config,
                                )
-                                for as_import in as_imports[from_import]
                            )


DanielNoord · 2026-08-11T20:48:04Z

This will need a rebase unfortunately. It is quite a big PR and is currently not on the top of my priority list for the next release, sorry!

Comment-only members of a parenthesised from-import were collapsed onto the opening import line as a single semicolon-joined comment. With the black profile that rewrote intentional WIP comments and produced lines that fail line-length checkers. Track those body comments separately and re-emit them as indented lines inside parenthesised wrapping; preserve the historical collapse for non-parenthesised wrap modes. Fixes PyCQA#1852 Signed-off-by: Alex Chen <l46983284@gmail.com>

DanielNoord

Sorry, still haven't gotten to this. I did do a rebase on main for you which uncovered an issue, hopefully you can fix it!

DanielNoord · 2026-08-17T21:04:00Z

+        captured.append(list(comments or []))
+        return original_with_comments(comments, *args, **kwargs)
+
+    monkeypatch.setattr("isort.output.with_comments", with_comments_probe)


This won't work for the mypyc compiled tests. Can we refactr this? If not we'll need to skip it.

The test test_combine_star_folds_body_comments_when_comments_are_enabled_issue_1852 monkeypatches isort.output.with_comments, which cannot work when isort is compiled with mypyc. Use the house _IS_COMPILED skipif pattern from tests/unit/test_main.py so the test is skipped in compiled builds.

alexchen-sys · 2026-08-17T21:40:11Z

Yes — reproduced the failure locally too; I had been testing without mypyc before, so the compiled legs never showed it on my side.

Fixed by skipping the monkeypatch-based test under mypyc, using the same _IS_COMPILED pattern as test_main.py:58. I ran locally on my pc, 13/13 pass; behavior is covered by the sibling e2e test_combine_star_folds_body_comments_issue_1852.

staticdev force-pushed the issue/1852-preserve-comment-only-import-lines branch from ee1bc23 to 468d670 Compare July 18, 2026 15:04

DanielNoord reviewed Jul 22, 2026

View reviewed changes

DanielNoord reviewed Jul 24, 2026

View reviewed changes

alexchen-sys force-pushed the issue/1852-preserve-comment-only-import-lines branch from 7e0c2ce to 0e3cd7e Compare July 25, 2026 11:52

DanielNoord reviewed Jul 25, 2026

View reviewed changes

DanielNoord requested a review from Copilot August 1, 2026 20:58

Copilot started reviewing on behalf of DanielNoord August 1, 2026 20:58 View session

Copilot AI reviewed Aug 1, 2026

View reviewed changes

alexchen-sys force-pushed the issue/1852-preserve-comment-only-import-lines branch from e3f9e7f to b383526 Compare August 14, 2026 18:44

DanielNoord force-pushed the issue/1852-preserve-comment-only-import-lines branch from b383526 to 247f001 Compare August 17, 2026 20:52

DanielNoord reviewed Aug 17, 2026

View reviewed changes

Uh oh!

Uh oh!

Conversation

alexchen-sys commented Jul 16, 2026

Summary

Test plan

Uh oh!

alexchen-sys commented Jul 17, 2026

Uh oh!

codecov Bot commented Jul 18, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Codecov Report

Uh oh!

alexchen-sys commented Jul 18, 2026

Uh oh!

alexchen-sys commented Jul 18, 2026

Uh oh!

alexchen-sys commented Jul 19, 2026

Uh oh!

alexchen-sys commented Jul 21, 2026

Uh oh!

DanielNoord left a comment

Choose a reason for hiding this comment

Uh oh!

alexchen-sys commented Jul 22, 2026

Uh oh!

DanielNoord left a comment

Choose a reason for hiding this comment

Uh oh!

DanielNoord left a comment

Choose a reason for hiding this comment

Uh oh!

alexchen-sys commented Jul 25, 2026

Uh oh!

DanielNoord left a comment

Choose a reason for hiding this comment

Uh oh!

alexchen-sys commented Jul 26, 2026

Uh oh!

alexchen-sys commented Jul 27, 2026

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

DanielNoord commented Aug 11, 2026

Uh oh!

DanielNoord left a comment

Choose a reason for hiding this comment

Uh oh!

DanielNoord Aug 17, 2026

Choose a reason for hiding this comment

Uh oh!

alexchen-sys commented Aug 17, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

codecov Bot commented Jul 18, 2026 •

edited

Loading